The overall goal of the Tissue Analysis Laboratory (the Core) is to provide technical and professional support for each Project. The Core at the University of Virginia has been in place for the past decade of the two previously funded prostate POI programs. All assessments will be made by two highly skilled, experienced genitourinary pathologists with expertise in examining mouse and human prostate tissues and in immunohistochemistry. Dr. Frierson will provide overall direction ofthe Core laboratory at the University of Virginia, while Dr. Lucia will lead the laboratory at the University of Colorado. The Core will have a large impact on the POI. as it provides tissue examination for in vivo models that compliment in vitro experiments. Comparative analysis of murine prostate cancers and clinical human prostate cancer specimens from different patient cohorts from two different laboratories will impact the field by clarifying signaling pathways in prostate cancer progression. The Core will have 3 Aims: Aim 1. Histologic analysis of cell cultures, xenografts, mouse models, and clinical human prostate tissue specimens. Specimens will be processed as archival (formalin-fixed, paraffin-embedded) samples or as frozen sections. In addition, Drs. Frierson and Lucia will use their expertise as pathologists to examine the prostate glands of transgenic mice to determine histopathologic changes induced by the genetic modifications. Aim 2. Immunohistochemical analysis and optimization of antibodies, specifically to determine their utility in formalin-fixed, paraffin-embedded material and. if necessary, in frozen sections. Drs. Frierson and Lucia will use the avidin-biotin immunoperoxidase technique and their immunohistochemical expertise to determine optimal reagent conditions and antibody staining in cell cultures, xenografts, mouse models, and clinical human prostate cancer specimens. Aim 3. Selection, preparation, and procurement of cells for laser microdissection. Drs. Frierson and Lucia have the ability to perform laser microdissection of prostate glands from human prostate tissues, transgenic mice, and xenografts for molecular studies